Temperature and Humidity Effects on MEMS Vibratory Gyroscope

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 001361-001390 ◽  
Author(s):  
Chandradip Patel ◽  
F. Patrick McCluskey ◽  
David Lemus
Keyword(s):  
Damage Mechanism ◽  
Consumer Electronics ◽  
Vibratory Gyroscopes ◽  
Root Cause ◽  
Vibratory Gyroscope ◽  
In Situ Data ◽  
Aging Test ◽  
Temperature And Humidity ◽  
Mems Gyroscopes ◽  
Gyroscope Sensor

MEMS vibratory gyroscopes are increasingly used in applications ranging from consumer electronics to aerospace and are now one of the most common MEMS products after accelerometers. Despite their widespread use, the performance of MEMS gyroscopes in harsh environments is still under question. While some studies have been conducted to understand the temperature dependent performance of MEMS gyroscopes, the effects of sustained exposure to temperature combined with other harsh environment stresses have not been well researched. Thus, it is necessary to quantify MEMS vibratory gyroscope performance under such conditions. This paper will focus on the combined effects of temperature and humidity only. Performance of the MEMS vibratory gyroscope will be evaluated over time at high temperature and high humidity conditions by conducting an aging test on a COTS (commercial of the shelf) single axis MEMS vibratory gyroscope having an operating temperature range from −40°C to 80°C. The gyroscope sensor will be exposed to 60 °C and 90% RH (Relative humidity) for 500 hours. In-situ data will be monitored to track any shifts in device output. Any permanent changes in the output signal will be traced back to their fundamental root cause damage mechanism.

Combined Temperature and Humidity Effects on MEMS Vibratory Gyroscope Sensor

2011 ◽  
Author(s):  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Long Term Effects ◽  
Mems Gyroscope ◽  
Vibratory Gyroscopes ◽  
Vibratory Gyroscope ◽  
Temperature And Humidity ◽  
Mems Gyroscopes ◽  
Zero Rate ◽  
Commercial Off The Shelf

Reliability and long term stability are the greatest challenges for commercialization of MEMS gyroscopes. Their vast use in different applications that required MEMS gyroscopes to function from medium to harsh environments make necessary to evaluate the performance of MEMS gyroscope under those conditions. This paper focuses on the combined long term effects of temperature and humidity on the performance of MEMS vibratory gyroscope. Performance of the MEMS gyroscope was evaluated over time by conducting temperature humidity bias (THB) test on a COTS (commercial off-the-shelf) single axis MEMS vibratory gyroscope having an operating temperature range from −40°C to +85°C. The gyroscope sensors were exposed to 60°C and 90%RH (Relative Humidity) for 500 hours. Six single axis gyroscopes were tested, three with in-situ device calibration and three without in-situ device calibration. Out of three MEMS vibratory gyroscopes tested without in-situ device calibration, it was observed that samples had minimum and maximum in-situ zero rate output (ZRO) drift of 1.3°/s and 2.2°/s respectively over 500 hours. These drifts were disappeared when gyroscope sensors were tested after six months by keeping at room condition. Other three single axis gyroscopes were tested in the same chamber with in-situ device calibration which didn’t show any major performance ZRO drift.

scholarly journals Significance of the Asymmetry of the Haltere: A Microscale Vibratory Gyroscope

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Rizuwana Parween
Keyword(s):  
Cross Sections ◽  
Strain Difference ◽  
Inertial Force ◽  
High Sensitivity ◽  
Ventral Surface ◽  
Small Scale ◽  
Mode Matching ◽  
Vibratory Gyroscopes ◽  
Vibratory Gyroscope ◽  
Mems Gyroscopes

Nature has evolved a beautiful design for small-scale vibratory gyroscopes in the form of halteres located in the metathorax region of the dipteran flies that detect body rotations based on the Coriolis principle. The specific design of the haltere is in contrast to the existing MEMS vibratory gyroscope, where the elastic beams supporting the proof mass are typically designed with symmetric cross-sections so that there is a mode matching between the actuation and sensing vibrations. The mode matching provides high sensitivity and low bandwidth. Hence, the objective of the manuscript is to understand the mechanical significance of the haltere’s asymmetry. In this study, the distributed Coriolis force and the corresponding bending stress by incorporating the actual mass variations along the haltere length are estimated. In addition, it is hypothesied that sensilla sense the rate of rotation based on the differential strain (difference between the final strain (strain due to the inertial and Coriolis forces) and the reference strain (strain due to inertial force)). This differential strain always occurs either on the dorsal or ventral surface of the haltere and at a distance away from the base, where the campaniform sensilla are located. This study brings out one specific feature—the asymmetric geometry of the haltere structure—that is not found in current vibratory gyroscope designs. This finding will inspire new designs of MEMS gyroscopes that have elegance and simplicity of the haltere along with the desired performance.

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

Novel FIB Use for Failure Analysis of MEMS Gyroscopes

2016 ◽  
Author(s):  
Nathan Wang ◽  
Saunil Shah ◽  
Camille Garcia ◽  
Vicente Pasating ◽  
George Perreault
Keyword(s):  
Thin Films ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
New Techniques ◽  
Unique Challenge ◽  
Root Cause ◽  
Large Size ◽  
Mems Gyroscopes

Abstract MEMS samples, with their relatively large size and weight, present a unique challenge to the failure analyst as they also included thin films and microstructures used in conventional integrated circuits. This paper describes how to accommodate the large MEMS structures without skimping on the microanalyses needed to get to the root cause. Investigations of tuning folk gyroscopes were used to demonstrate these new techniques.

Performance and Reliability of MEMS Gyroscopes and Packaging at High Temperatures

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000359-000366 ◽  
Author(s):  
Patrick McCluskey ◽  
Chandradip Patel ◽  
David Lemus
Keyword(s):  
High Temperature ◽  
Indoor Environment ◽  
Elevated Temperatures ◽  
High Sensitivity ◽  
Effect Of Temperature ◽  
Gps Tracking ◽  
Mems Gyroscope ◽  
Mems Gyroscopes ◽  
Gyroscope Sensor

Elevated temperatures can significantly affect the performance and reliability of MEMS gyroscope sensors. A MEMS vibrating resonant gyroscope measures angular velocity via a displacement measurement which can be on the order on nanometers. High sensitivity to small changes in displacement causes the MEMS Gyroscope sensor to be strongly affected by changes in temperature which can affect the displacement of the sensor due to thermal expansion and thermomechanical stresses. Analyzing the effect of temperature on MEMS gyroscope sensor measurements is essential in mission critical high temperature applications, such as inertial tracking of the movement of a fire fighter in a smoke filled indoor environment where GPS tracking is not possible. In this paper, we will discuss the development of the high temperature package for the tracking application, including the characterization of the temperature effects on the performance of a MEMS gyroscope. Both stationary and rotary tests were performed at room and at elevated temperatures on 10 individual single axis MEMS gyroscope sensors.

Inspections of Tread Damaged Wheelsets

2008 ◽  
Author(s):  
Scott M. Cummings ◽  
Don Lauro
Keyword(s):  
Impact Load ◽  
Damage Mechanism ◽  
Location Data ◽  
Root Cause ◽  
Frequent Use ◽  
Crack Band ◽  
Defect Prevention ◽  
Research Consortium ◽  
High Level ◽  
Contact Position

Inspections of 163 wheelsets conducted by the Wheel Defect Prevention Research Consortium (WDPRC) have produced critical information in identifying the high-level root causes of tread damage. While the overall wheel tread damage problem appears to be split fairly evenly between shelling and spalling, the type of tread damage on a wheelset is strongly linked to the type of car from which it was removed. Coal car wheels, which generally run in heavy axle load, high-mileage service with minimal yard handling, are almost exclusively subject to shelling damage with little spalling damage. On the other hand, mixed freight cars, such as tank cars and covered hopper cars, tend to run in lower mileage service with more yard handling, resulting in fewer loading cycles under lighter stress and more frequent use of hand brakes. Not surprisingly then, wheels from these types of cars were observed to have a mix of spalling and shelling damage, with spalling being the predominant damage mechanism. Nearly every high impact wheel (HIW) inspected showed either spalling, shelling, or some combination of the two. As expected, wheel impact load detector (WILD) readings and radial tread run out data were found to be related. Rim thickness deviations and rim lateral face deviations were not found to be important contributors to shelling. The lateral tread location of radial run-out deviations and crack bands could be an important clue in discovering the root cause of shelling. Radial run-out data and crack band location data shows that shelling damage is most prevalent outboard of the tapeline. This is the expected wheel/rail contact position of a wheel in the lead wheelset position of a truck, while riding on the low (inside) rail of a curve. Many of the wheels that were removed for wear causes were found to have noncondemnable shelling and spalling, indicating that tread damage is more prevalent than repair records would indicate.

The Hygrothermal Aging Life Models of Solid Propellant

2012 ◽  
Vol 452-453 ◽  
pp. 1235-1239
Author(s):  
Jian Wei Lai ◽  
Xin Long Chang ◽  
Sun Tao ◽  
Peng Ya Fang ◽  
Wan Lei Liu
Keyword(s):  
Environmental Factors ◽  
Solid Propellant ◽  
Life Prediction ◽  
Storage Life ◽  
Single Factor ◽  
Hygrothermal Aging ◽  
Significance Analysis ◽  
Aging Test ◽  
Temperature And Humidity ◽  
Life Model

The temperature and humidity are two main environmental factors, which have influence on the life of solid propellant. Comparing with single factor aging life model, hygrothermal aging life model is more feasible, which takes temperature and humidity into consideration. In this paper two hygrothermal aging life models were established. The data of hygrothermal aging test of solid propellant was used for multiregression. According to significance analysis and comparison of two models, it was shown that two models both fit the test data well. Storage life of the solid propellant under normal condition was obtained by using the life models. The results of the research can provide reference for storage life prediction of solid propellant.

scholarly journals Frequency Split Analysis of a Ring Vibratory Gyroscope Based on Harmonic Transformation of Parametric Errors

2020 ◽  
Author(s):  
Xiang Xi ◽  
Yongmeng Zhang ◽  
Jiangkun Sun ◽  
Xuezhong Wu
Keyword(s):  
Ring Resonator ◽  
Angular Rate ◽  
Ring Resonators ◽  
Harmonic Waves ◽  
Navigation Systems ◽  
Fem Modeling ◽  
Roundness Error ◽  
Vibratory Gyroscopes ◽  
Vibratory Gyroscope ◽  
Frequency Split

Abstract Ring vibratory gyroscopes are important angular rate sensors widely used in inertial navigation systems. A highly symmetrical resonator is the core part of the ring vibratory gyroscope. Frequency split is a key parameter which denotes the level of unbalanced mass and stiffness of the resonator. Many research works focus on the precise machining of the resonator for the sake of eliminating frequency split. However, for metallic ring resonators, the decrease of frequency split is not always proportional to the promotion of geometric accuracy. This paper investigates the frequency split of the ring resonator gyroscope caused by parametric errors including geometric and material imperfection via a method of harmonic transformation. The roundness error of the ring resonator is extracted, and then decomposed to a series of orders of harmonic waves. Transformation results show that for the tested resonator, its first 20 orders of harmonic waves contain the main components of the roundness error. Then a precise FEM modeling is built for frequency split analysis. The simulation result shows that the roundness error of the resonator can cause a frequency split of 0.6 Hz, which accounts for 16.2 % of the total frequency split. Based on the metallographic observation and grouping experiment of different metallic resonators, it is deduced that the main frequency split is caused by material heterogeneity. It shows that the material homogenization is as important as precise machining for the resonator of small frequency split. The proposed research provides an instruction to manufacture high quality metallic resonators.

Performance Degradation of the MEMS Vibratory Gyroscope in Harsh Environments

2011 ◽  
Author(s):  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Test Procedure ◽  
Original Position ◽  
Harsh Environments ◽  
Mems Gyroscope ◽  
Vibratory Gyroscope ◽  
Wide Range ◽  
Before And After ◽  
Mems Gyroscopes ◽  
Baseline Testing ◽  
Commercial Off The Shelf

The use of MEMS gyroscopes in a wide range of applications requiring then to function from medium to harsh environments make it necessary to evaluate the performance of MEMS gyroscopes under those conditions. This paper focuses on the effects of elevated temperature and humidity on the performance of MEMS vibratory gyroscopes. Performance of the MEMS gyroscope was evaluated by conducting Highly Accelerated Stress Testing (HAST) on a COTS (commercial-off-the-shelf) single axis MEMS vibratory gyroscope having an operating temperature range from −40C to +105C. The gyroscope sensors were exposed to 130°C and 85% relative humidity with a pressure of 33.3 psia or 230 kPa for 96 hours. Pre-baking and post-baking tests were conducted before and after HAST at 125C for 24 hours respectively. Also, stationary baseline testing (SBT) and rotary baseline testing (RBT) were performed before and after the pre-baking, HAST and post-baking tests to measure any permanent shift during the respective test. A preliminary result shows that the MEMS gyroscope output degraded in the pre-baking test and HAST; while it showed a recovery in post-baking test. After completing the entire test procedure, it was observed that MEMS gyroscope output didn’t come back to the original position, and resulted in a permanent output shift of 1.85deg/s.

Performance of MEMS Vibratory Gyroscope under Harsh Environments

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000633-000654 ◽  
Author(s):  
Chandradip Patel ◽  
Patrick McCluskey
Keyword(s):  
Temperature Effect ◽  
High Frequency ◽  
Microelectromechanical Systems ◽  
Rate Of Change ◽  
Harsh Environments ◽  
Harsh Environment ◽  
Thermal Cycles ◽  
Mems Gyroscope ◽  
Vibratory Gyroscope ◽  
Mems Gyroscopes

Microelectromechanical systems (MEMS) gyroscope is a sensor that measures the rate of change in an angular position of an object. MEMS vibratory gyroscopes are increasingly used in applications ranging from consumer electronics to aerospace and are now one of the most common MEMS products after accelerometers.With advances in fabrication technologies, the low-cost MEMS gyroscope has opened up a wide variety of applications with environmental conditions ranging from medium to harsh. Despite their widespread use, the performance of MEMS gyroscopes in harsh environments is still under question. While some studies have been conducted to understand the effects of high mechanical shock, high frequency vibration and high frequency acoustic environment on the MEMS gyroscopes,the effects of sustained exposure to temperature combined withother harsh environment stresseshave not been well researched.Thus, it is necessary to quantify MEMS vibratory gyroscope performance under such conditions.This research reviews current harsh environment studies anddemonstrates the effects of an elevated temperature and sustained exposure to temperature combined humidity on the MEMS vibratory gyroscope. In order to quantify such effects, several tests have been performed. A short-term temperature effect on MEMS gyroscope was examined through temperature characterization test forfive thermal cycles at wider temperature ranges. A long-term temperature effect on the MEMS gyroscope was inspected through 500 thermal cycles; while, combined effects of temperature and humidity was studied through temperature humidity bias(THB) test and highly accelerated stress test (HAST).

Sign in / Sign up

Export Citation Format

Share Document